radio
/ˈradjo/masculine
The Spanish word for "radius" is radio.
radio is used to refer to the length of this line segment.
Meaning: length of this line segment (noun)
Which one should you use?
The word radio is a homonym. It can mean both 'radius' and 'radio' (the communication device or broadcast).
How do you pronounce it?
/ˈradjo/
What mistakes should you avoid?
English speakers may mistakenly use the feminine form la radio when referring to the mathematical radius, but 'radius' is always masculine: el radio.
Did you know?
- In Spanish anatomy, the bone in the forearm is called el radio, mirroring the mathematical term because of its shape.
- The Spanish word radio is a doublet of rayo, meaning 'ray' or 'lightning bolt'. Both words descend from the same Latin root radius, which originally referred to the spoke of a wheel.
- While el radio is the mathematical radius, the communication device is often called la radio in Spain. This gender shift helps listeners distinguish between a geometric line and a broadcast signal.
Examples in context
- ¿Cómo calcular el radio de una circunferencia?How do you calculate the radius from the circumference?This sentence is useful for learning how to ask about calculating the radio of a circle.Tatoeba #1063047 by Shishir, translation #5930324 by mailohilohi
- El radio de la Tierra asciende a 6400 km.The radius of the Earth is 6400 km.This sentence is useful for stating the radio of the Earth.Tatoeba #1520277 by Espi, translation #1520257 by shanghainese
- El radio del círculo es de cinco centímetrosThe radius of the circle is five centimeters
- Usa una regla para medir el radio de ese círculoUse a ruler to measure the radius of that circle
- El radio de este círculo es muy pequeño.The radius of this circle is very small.
Example conversation
Lucía and Javier are solving a geometry problem together.
- LucíaNo encuentro el radio en este ejercicio.I can't find the radius in this exercise.
- JavierMira, el radio es la mitad del diámetro.Look, the radius is half of the diameter.
- LucíaEs verdad, ahora ya lo veo, Javier.That's true, I see it now, Javier.
- JavierPerfecto, ahora puedes terminar el cálculo.Perfect, now you can finish the calculation.
Sources
- Wiktionary, “radius” translations and entries radio, CC BY-SA 4.0, dump of 2026-09-26.
- Word origins: Wiktionary entries radio, CC BY-SA 4.0.
- Example sentences: Tatoeba CC BY 2.0 FR.
